Electrocardiography (ECG) is a well established method of measuring the set of electrical events that are intrinsic to the heart's function. Electrocardiography has found applications in a wide variety of clinical situations including resting diagnostic procedures; surgical and emergency room procedures; cardiac care; critical care; ambulatory monitoring; stress diagnostic procedures; and in providing remote patient monitoring.
Biomedical electrodes are used to transmit ECG potentials from the body, via lead wires, to an electrocardiograph to record electrocardiographic signals. The lead wire connection to the electrocardiograph can be direct or indirect, as through telemetry equipment. Biomedical electrodes may be of the reusable type but for reasons of hygiene and economy are often of the disposable type.
A disposable biomedical electrode is typically composed of a conductive and adhesive layer attached to a conductive layer of an insulative substrate. The adhesive layer retains the electrode to the skin of the patient. A lead wire is attached to the conductive layer of the substrate by a lead clip, e.g. of the alligator type.
The current offering of disposable electrodes suffer from a limitation in that they typically provide only one connection site for the lead wire. This is usually via a tab on the periphery of a generally rectangular or circular electrode. This limitation requires the technician to devote additional time in properly positioning the electrode on the patient to ensure the availability of a connection point and restricts the patient's range of movement while attached to the lead wires. Proper electrode positioning is also required due to the shear stress applied to the electrode by the weight and angle of the lead wire. This stress acts on the adhesive layer, which may include a conductive gel, and causes the electrode to lift up or roll over from its position in contact with the patient's skin. Such an occurrence reduces not only the area in which the electrode is in contact with the skin but also the overall quality of the connection itself, thereby introducing error in the ECG measurement. In a worst case scenario, either the electrode or lead wire will detach due to the stress and angle of the lead wire, causing loss of the ECG signal. This requires repositioning or replacement of the electrode.
It is therefore desirable to provide an electrode that facilitates connection of the lead wire to the electrode and reduces the electrode's tendency to lift up or roll-over due to stresses exerted by the lead wire.